In chemistry, fractional crystallization is a method of refining

Refining

Refining is the process of purification of a substance or a form. The term is usually used of a natural resource that is almost in a usable form, but which is more useful in its pure form. For instance, most types of natural petroleum will burn straight from the ground, but it will burn poorly...

 substances based on differences in solubility. If a mixture of two or more substances in solution is allowed to crystallize, for example by allowing the temperature of the solution to decrease, the precipitate will contain more of the least soluble substance. The proportion of components in the precipitate will depend on their solubility products. If the solubility products are very similar a cascade process

Cascade (chemical engineering)

In chemical engineering, a cascade is a plant consisting of several similar stages with each processing the output from the previous stage. Cascades are most commonly used in isotope separation, distillation and other separation or purification processes....

 will be needeed to effectuate a complete separation.

This technique is often used in chemical engineering

Chemical engineering

Chemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...

 to obtain very pure substances, or to recover saleable products from waste solutions.

See also

• Crystal
  Crystal
  A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...
  
  
• Crystal structure
  Crystal structure
  In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...
  
  
• Crystallite
  Crystallite
  Crystallites are small, often microscopic crystals that, held together through highly defective boundaries, constitute a polycrystalline solid. Metallurgists often refer to crystallites as grains.- Details :...
  
  
• Crystallization
  Crystallization
  Crystallization is the process of formation of solid crystals precipitating from a solution, melt or more rarely deposited directly from a gas. Crystallization is also a chemical solid–liquid separation technique, in which mass transfer of a solute from the liquid solution to a pure solid...
  
   and engineering aspects
• Fractional freezing
  Fractional freezing
  Fractional freezing is a process used in process engineering and chemistry to separate two liquids with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals, or by partial crystallization of a liquid, for example "freeze...
  
  
• Laser Heated Pedestal Growth
• Recrystallization (chemistry)
  Recrystallization (chemistry)
  -Chemistry:In chemistry, recrystallization is a procedure for purifying compounds. The most typical situation is that a desired "compound A" is contaminated by a small amount of "impurity B". There are various methods of purification that may be attempted , which includes recrystallization...
  
  
• Seed crystal
  Seed crystal
  A seed crystal is a small piece of single crystal/polycrystal material from which a large crystal of the same material typically is to be grown...
  
  
• Single crystal
  Single crystal
  A single crystal or monocrystalline solid is a material in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no grain boundaries...
  
  
• Pumpable ice technology
  Pumpable ice technology
  Pumpable ice technology is a technology to produce fluids or secondary refrigerants also called coolants with a viscosity of water or jelly and the cooling capacity of ice...